how do i stop videos from automatically playing after i download them?

I am running firefox for android .I have tried to download flash block and flash blocker but it said it was not compatible. Is there something in about:config I can change to stop auto play after download.

I am running firefox for android .I have tried to download flash block and flash blocker but it said it was not compatible. Is there something in about:config I can change to stop auto play after download.